Extracellular alkaline shifts in rat hippocampal slice are mediated by NMDA and non-NMDA receptors

J Neurophysiol. 1992 Jul;68(1):342-4. doi: 10.1152/jn.1992.68.1.342.


1. The pharmacology of synaptically evoked extracellular alkaline shifts was studied in the CA1 area of rat hippocampal slices. 2. Stimulus-evoked alkalinizations were unaffected by 2-amino-5-phosphonovalerate (APV) (20 microM). 3. 6-Cyano-7-nitro-nitroquinoxaline-2,3-dione (CNQX) (10 microM) inhibited the alkalinizations. In the continued presence of CNQX, an APV-sensitive, picrotoxin-insensitive, alkaline shift was elicited in low Mg2+ media. 4. Antidromic stimulation produced small alkaline shifts in comparison with orthodromic activation. 5. Our results demonstrate that in the hippocampal CA1 region, synaptically evoked alkalinizations can arise through both N-methyl-D-aspartate (NMDA) and non-NMDA glutamate receptors. These responses cannot be explained by cell firing per se.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 2-Amino-5-phosphonovalerate / pharmacology
  • 6-Cyano-7-nitroquinoxaline-2,3-dione
  • Animals
  • Electric Stimulation
  • Extracellular Space / drug effects
  • Extracellular Space / metabolism*
  • Hippocampus / drug effects
  • Hippocampus / metabolism*
  • Hydrogen-Ion Concentration
  • In Vitro Techniques
  • Quinoxalines / pharmacology
  • Rats
  • Receptors, N-Methyl-D-Aspartate / drug effects
  • Receptors, N-Methyl-D-Aspartate / physiology*
  • Receptors, Neurotransmitter / drug effects
  • Receptors, Neurotransmitter / physiology*
  • Synapses / drug effects


  • Quinoxalines
  • Receptors, N-Methyl-D-Aspartate
  • Receptors, Neurotransmitter
  • 6-Cyano-7-nitroquinoxaline-2,3-dione
  • 2-Amino-5-phosphonovalerate